The present disclosure relates to a communication system and an operating method thereof, and particularly, to a communication system and an operating method thereof, which generate system analysis information on a remote terminal unit (RTU) of a supervisory control and data acquisition (SCADA) system to control each RTU.
A SCADA system is defined as a communication system for collecting, receiving, recording, and displaying, at a remote control center (RCC), state signal data (or points) of a plurality of RTUs using an analog or digital signal on a communication path, and allowing the RCC to supervise and control each of the RTUs.
The SCADA system is typically a system for supervising and controlling, in a centralized manner, many kinds of remote facilities such as power generation, transmission, and distribution facilities, a petrochemical plant, an iron and steel making facility, and a factory automation facility, etc.
The SCADA system performs functions of a supervising system that performs a pre-determined operation according to a state of an RTU. For example, the SCADA system performs an alarm function, a supervising and controlling function for selectively operating the RTU manually or automatically, and an instructing function or a displaying function of a supervising system that receives, displays, or records a state signal of the RTU.
The RCC of the SCADA system periodically obtains a state signal (or state value) at determined times, generates system analysis information (or unique algorithm) used for controlling the plurality of RTUs on the basis of the obtained state signals, and controls each of the RTUs on the basis of the generated system analysis information.
Furthermore, the RCC may receive the state signal (or value) (e.g. “open” or “close”) from each RTU and at the same time, receive signal quality information (e.g. “good” or “suspect”) including whether each state signal is normal or erroneous, generate RTU analysis information, which is analysis information on each RTU, in response to the received signal quality information, and may collect the RTU analysis information on each RTU to generate system analysis information that is analysis information on the plurality of RTUs.
For example, when receiving, from an RTU, an “open” state signal together with normal signal information (e.g. “good”) including information that the corresponding “open” state signal is normal, a control device 100 generates RTU analysis information that the “RTU” is “open” on the basis of the corresponding “open” state signal, and generates system analysis information for analyzing the plurality of RTUs including “open RTUs” by reflecting the RTU analysis information that “RTU is opened”.
On the other hand, for example, when receiving, from an RTU, a “close” (i.e. connected) state signal together with erroneous signal information (e.g. “suspect”) including information that the corresponding “close” states signal is an erroneous signal, the control device 100 generates RTU analysis information that “the RTU” is “open” on the basis of the “open” state signal received therewith at the time of receiving “good” signal quality data, which is last received before receiving signal quality data of “suspect” instead of the corresponding “close” state signal in response to the erroneous signal information (“e.g. suspect”), and reflects the RTU analysis information to generate the system analysis information for analyzing the plurality of RTUs including “opened RTUs”.
Referring to FIG. 1, the control device 100 may obtain signal quality data of “GOOD” together with an “OPEN” state signal (or “a first state signal”) (0) obtained from a first RTU 301, and may execute system analysis according to the obtained state signal and signal quality data.
An example of the RTU may include a circuit breaker.
After receiving the first state signal (0), when obtaining a “CLOSE” state signal (or a second state signal) (1) and signal quality data of “GOOD” from the first RTU, the control device 100 may trust the “CLOSE” state signal (1) and generate state estimation data (e.g. “connected circuit breaker”) for the first RTU 301 in response to the “CLOSE” state signal (1).
However, unlike this, after receiving the first state signal, when obtaining “CLOSE” state signal (the second state signal) (2) and signal quality data of “SUSPECT” from the first RTU, the control device 100 may not trust the “CLOSE” state signal (2) and may generate state estimation data (“opened circuit breaker”) for the first RTU 301 in response not to the “CLOSE” state signal (2), but to the “OPEN” state signal (the first state signal) (0) received together with the last “GOOD” signal quality data.
Accordingly, as described above, in analyzing the system analysis information, matching between the signal quality data and each state signal obtained from each RTU is significant.
However, for the signal quality data, a “good” signal may be changed to a “suspect” signal and the “suspect” signal may be analyzed as the “good signal”, due to a physical limitation in communication through which each signal quality data is received or an error occurring in each RTU itself regardless of the quality of an actual state signal.
Accordingly, operations are necessary to determine whether the signal quality data from each RTU is erroneous.